How to restrict the CPU and Memory Usage of a process on CentOS?

To restrict CPU and memory usage of a process on CentOS, you can use cgroups (Control Groups) and the related utilities that come with the libcgroup package.

Here's a basic overview of how to use cgroups to limit CPU and memory usage:

1. Install libcgroup tools:

sudo yum install libcgroup libcgroup-tools

2. Start and enable the cgconfig service:

sudo systemctl start cgconfig
sudo systemctl enable cgconfig

3. Create a Control Group:

For this example, we'll create a control group named limited_group that restricts CPU and memory.

First, configure the CPU:

sudo cgcreate -g cpu:/limited_group

Now, set the CPU limit. For instance, to allocate only 20% of the CPU to limited_group:

echo 200000 > /sys/fs/cgroup/cpu/limited_group/cpu.cfs_quota_us
echo 1000000 > /sys/fs/cgroup/cpu/limited_group/cpu.cfs_period_us

Next, configure memory. Create the memory group:

sudo cgcreate -g memory:/limited_group

To limit memory usage to, for example, 500MB:

echo 500M > /sys/fs/cgroup/memory/limited_group/memory.limit_in_bytes

4. Assign a Process to the Control Group:

To add a process to this group, you need the PID of the process. For example, if the PID is 12345:

echo 12345 > /sys/fs/cgroup/cpu/limited_group/tasks
echo 12345 > /sys/fs/cgroup/memory/limited_group/tasks

5. Make the configuration persistent across reboots:

To make these configurations persistent, you would typically configure the /etc/cgconfig.conf and /etc/cgrules.conf files.

In /etc/cgconfig.conf:

group limited_group {
    cpu {
        cpu.cfs_quota_us = 200000;
        cpu.cfs_period_us = 1000000;
    }
    memory {
        memory.limit_in_bytes = 500M;
    }
}

In /etc/cgrules.conf:

*:myuser cpu,memory limited_group/

Replace myuser with the name of the user whose processes you want to restrict.

Finally, restart the cgconfig service:

sudo systemctl restart cgconfig

Note: These are just basic configurations. Cgroups offer much more advanced controls, and it's essential to test any configurations in a non-production environment first. Adjustments might be required based on specific needs and system behavior.